Circuit configuration for matching an amplifier to a radio-frequency line, and use of the circuit configuration

Abstract

A circuit for matching an amplifier to a radio-frequency line is described. In order to minimize the number of components required for matching the amplifier to different frequency bands, the circuit has a first capacitance for outputting the negative half-cycle of the transmission signal, which is rectified by a diode and is stored in a second capacitance. The stored negative voltage is, if required, fed back via two resistors and an inductance to a further diode.

I claim:  
     
       1. A circuit configuration for matching an amplifier to a radio-frequency line, the circuit configuration comprising: 
       a first diode having a first terminal and a second terminal to be connected to a first potential;  
       an inductor having a first terminal and a second terminal;  
       a first capacitance having a first terminal connected to the radio-frequency line and a second terminal connected to said first terminal of said first diode and to said first terminal of said inductance;  
       a second diode having a first terminal coupled to said first capacitance and a second terminal;  
       a first resistor having a first terminal connected to said second terminal of said inductance and a second terminal;  
       a second resistor having a first terminal connected to said second terminal of said first resistor and a second terminal;  
       a switching device having a first terminal connected to said second terminal of said first resistor and to said first terminal of said second resistor, said switching device having a second terminal to be connected to a second potential; and  
       a second capacitance having a first terminal connected to said second terminal of said second resistor and to said second terminal of said second diode, said second capacitance having a second terminal to be connected to the first potential.  
     
     
       2. The circuit configuration according to  claim 1 , wherein said first diode is a PIN diode. 
     
     
       3. The circuit configuration according to  claim 1 , wherein said second diode is a Schottky diode. 
     
     
       4. The circuit configuration according to  claim 1 , wherein said switching device is an audio frequency transistor. 
     
     
       5. The circuit configuration according to  claim 1 , including a third resistor having a first terminal connected to said first terminal of said inductance and a second terminal connected to said first terminal of said second diode. 
     
     
       6. In combination with a dual-band radio telephone having a transmission path which can be used for different frequency bands, a circuit configuration for matching an amplifier to the different frequency bands, the circuit configuration comprising: 
       a first diode having a first terminal and a second terminal to be connected to a first potential;  
       an inductor having a first terminal and a second terminal;  
       a first capacitance having a first terminal connected to the radio-frequency line and a second terminal connected to said first terminal of said first diode and to said first terminal of said inductance;  
       a second diode having a first terminal coupled to said first capacitance and a second terminal;  
       a first resistor having a first terminal connected to said second terminal of said inductance and a second terminal;  
       a second resistor having a first terminal connected to said second terminal of said first resistor and a second terminal;  
       a switching device having a first terminal connected to said second terminal of said first resistor and to said first terminal of said second resistor, said switching device having a second terminal to be connected to a second potential; and  
       a second capacitance having a first terminal connected to said second terminal of said second resistor and to said second terminal of said second diode, said second capacitance having a second terminal to be connected to the first potential.